1. Field of the Invention
The present invention relates to a cabinet of electronic equipment (e.g., a liquid crystal television receiver), which is assembled of two open box-type cases.
2. Description of Related Art
A conventional cabinet of a liquid crystal television receiver will be described as an example with reference to the attached drawings.
FIG. 5 is an exploded diagram of the conventional liquid crystal television receiver, in which a main circuit board and a rear case are detached to be viewed. As shown in FIG. 5, a cabinet of the liquid crystal television receiver 1 includes a box-type front case 2 with an open rear side in which a liquid crystal module 4 and a main circuit board 5 are arranged, and a box-type rear case 3 with an open front side that is fit in the open rear part of the front case 2 so that they are engaged with each other. An open front part of the rear case 3 is formed thin to have a step on its outer face, which is engaged with the open rear part of the front case 2. When they are engaged with each other, a plurality of hooks 2a formed on the inner wall of the open rear part of the front case 2 respectively engage corresponding elongated holes as a plurality of engaging holes 3a formed in the open front part of the rear case 3 to pass through its wall, so that the front case 2 and the rear case 3 are coupled to each other.
The front case 2 is provided with a sheet metal attachment 6 for attaching the main circuit board 5 to the rear side of the liquid crystal module 4 as shown in FIG. 5. The sheet metal attachment 6 is provided with a plurality of backup parts 61 each of which has a threaded hole 61a, and they are formed by cutting and raising the sheet metal attachment 6. The main circuit board 5 is fixed to the sheet metal attachment 6 with screws 7 that pass through a plurality of holes 51 formed in the main circuit board 5 and are fastened to threaded holes 61a of the backup parts 61 of the sheet metal attachment 6.
FIG. 6 shows a vertical section of a die for molding the conventional rear case, FIG. 7 shows a cross section of the die cut along the dashed dotted line in FIG. 6, and FIG. 8 is a perspective view of the conventional rear case viewed from the open side. As shown in FIGS. 6 and 7, a first die 101 having a recess and a second die 102 having a salient are combined so that the recess and the salient are engaged with each other when the rear case 3 is molded. On this occasion, the recess and the salient are opposed to each other with a predetermined space between them, which forms a cavity 103. The rear case 3 is molded by filling a melted resin material (hereinafter referred to as a “material” simply) in the cavity 103 and curing the material. The material is injected into the cavity 103 through an injection 101a that is formed to pass through the first die 101. The first die 101 is provided with a plurality of protrusions 101b at positions corresponding to the plurality of engaging holes 3a of the rear case 3 (see FIG. 5) so as to form the engaging holes 3a. The injected material fills the cavity 103 and finally goes around the protrusion 101b from its rear (the right in FIG. 6) to its both sides (the front and the back of paper of FIG. 6) so as to reach the vertical face of the second die 102, and flows of the material from both sides go to the front of the protrusion 101b (the left in FIG. 6) so as to meet at the middle part.
Therefore, when the molded rear case 3 is viewed from the open side as shown in FIG. 8, a so-called weld line 3b may be generated at each part where the flows of the material meet as shown in FIG. 9 because the meeting flows of the material may be cured before they are mixed completely. This weld line 3b is a type of defective molding that causes deterioration of strength of the resin product. As a result, if the hook 2a and the engaging hole 3a are hard to catch each other when the front case 2 and the rear case 3 are coupled, a stress exerting on the periphery of the engaging hole 3a of the rear case 3 may cause a crack along the weld line 3b resulting in a breakage of the rear case 3.
JP-A-H6-311459, Japanese Utility Model No. 3090702 and JP-A-S64-37183 disclose assembly structures of cabinets of television receivers, but they do not disclose any structure of the cabinet as described above, in which the rear case has engaging holes with which hooks of the front case are engaged.